Very high data rates require large transmission bandwidths. The required transmission bandwidth for some applications or deployments can exceed the transmission bandwidth that is supplied by a single carrier or channel. In order to support these data rates, carrier aggregation, (CA, or sometimes channel aggregation) may be used. Using carrier aggregation, it is possible to utilize more than one carrier and thereby increase the overall transmission bandwidth available for very high data rate communication. These channels or carriers may be in contiguous elements of the spectrum, or they may be in different bands.